Single-acting, gas operated pump
Patent 4681518 Issued on July 21, 1987. Estimated Expiration Date: 
December 20, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 20, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorAssigneeApplicationNo. 06/811863 filed on 12/20/1985US Classes:417/395, Diaphragm91/347Coil spring moves laterally relative to coil axisExaminersPrimary: Smith, Leonard E.International ClassesF04B 9/127 (20060101)F01L 35/00 (20060101) F04B 9/00 (20060101) AbstractA single-acting, gas operated, pump method and apparatus including a pump body having a main chamber divided by a reciprocating piston assembly into a gas driving chamber and a liquid pumping chamber, a spring for biasing the piston assembly into one of its two end positions, a reciprocating control valve controlling the flow of driving gas to and from the gas driving chamber, a snap-acting spring mechanically coupling the control valve to the reciprocating movement of the piston assembly, and a counteracting spring for biasing the control valve toward one of its two positions. | |
